Erik ten Hag said he will deal with Marcus Rashford after omitting the forward from Manchester United’s squad for their 4-2 FA Cup victory at Newport County because of an ­“internal matter”, raising further questions about indiscipline within his squad. Rashford reported ill for training on Friday, hours after allegedly being pictured at a nightclub in Belfast. The 26-year-old England striker is reported to have attended Thompsons Garage nightclub on Thursday before ­flying home by private jet on Friday ­morning. Rashford travelled to Northern Ireland on Wednesday to visit his former United youth teammate ­Ro-Shaun Williams, who recently signed for the domestic champions, Larne. Ten Hag ruled ­Rashford out of his side’s trip to Newport on Friday because of illness. In a statement on Sunday, United said Rashford “stayed at Carrington to train as he recovers”. Ten Hag, speaking after United’s win in south Wales, said: “He reported ill and the rest is an internal matter.” Ten Hag refused to expand when asked why Rashford’s absence was deemed an in-house matter. “It is an internal matter. As I said, we will deal with it. I will deal with it.” In November, the United manager criticised Rashford’s “­unacceptable” decision to attend a nightclub hours after a 3-0 Manchester derby defeat. At the time Ten Hag said he spoke with the England forward, who apologised for his actions. “He’s very motivated to put things right,” he said. “He’s totally with us.” A couple of months earlier, Ten Hag said he inherited a “no-good culture” upon taking the United job and ­pre­viously jettisoned Jadon Sancho, now on loan at his previous club Borussia Dortmund, because of his below-par training performances. The Dutchman has also previously ordered Anthony Martial to train alone. Rashford has scored four goals across all competitions this season, including in United’s most recent two Premier League matches, against Nottingham Forest and Tottenham. Last month the former United midfielder and academy coach Nicky Butt blamed the environment at the club as a factor for Rashford’s struggles. “Rashford is a world-class ­talent who’s just not happy in his life, or football, or whatever it is,” Butt said. “He’s just not happy. I can’t compare myself to Marcus because he’s in a shithole of a changing room right now, let’s be perfectly honest. I was in an unbelievable ­dressing room. Marcus isn’t.” Rasmus Højlund capped the ­scoring for United at Rodney Parade, finding the net in stoppage time after they averted a major scare. United led through early goals from the captain, Bruno Fernandes and Kobbie Mainoo, his first senior goal, but Newport pulled level at 2-2 early in the second half. Antony regained United the lead before Højlund’s late strike.